Data commit

Task/Hofstadter-Figure-Figure-sequences/Sidef/hofstadter-figure-figure-sequences.sidef

@@ -0,0 +1,35 @@
+var r = [nil, 1]
+var s = [nil, 2]
+
+func ffsr(n) {
+  while(r.end < n) {
+    r << s[r.end]+r[-1]
+    s << [(s[-1]+1 .. r[-1]-1)..., r[-1]+1].grep{ s[-1] < _ }...
+  }
+  return n
+}
+
+func ffr(n) { r[ffsr(n)] }
+func ffs(n) { s[ffsr(n)] }
+
+printf("  i: R(i) S(i)\n")
+printf("==============\n")
+{ |i|
+    printf("%3d:  %3d  %3d\n", i, ffr(i), ffs(i))
+} << 1..10
+printf("\nR(40)=%3d S(960)=%3d R(41)=%3d\n", ffr(40), ffs(960), ffr(41))
+
+var seen = Hash()
+
+{|i| seen{ffr(i)} := 0 ++ } << 1..40
+{|i| seen{ffs(i)} := 0 ++ } << 1..960
+
+if (seen.count {|k,v| (k.to_i >= 1) && (k.to_i <= 1000) && (v == 1) } == 1000) {
+    say "All occured exactly once."
+}
+else {
+    var missed = { !seen.has_key(_) }.grep(1..1000)
+    var dupped = seen.grep { |_, v| v > 1 }.keys.sort
+    say "These were missed: #{missed}"
+    say "These were duplicated: #{dupped}"
+}